Periscopic apparatus for range finding, height finding



p June 12, 1928.

J. W. FRENCH PERISCOPIC APPARATUS FOR RANGEFINDING, HEIGHTFINDING a Filed Oct. 24, 1922 2 Sheets-Sheet fillllllllllf t June 12, 1928.

J. W. FRENCH PERISCOPIC APPARATUS FOR RANGEFINDING, HEIGHTFINDING Filed 001;. 24.

1922 2 Sheets-Sheet 2 B Figllu;

Patented June 12, 1928.

1 UNITED STATES PATENT OFFICE.

JAMES WEIR FRENCH, O13 ANNIESLAND, GLASGOW, SCOTLAND, ASSIGNOR TO BARR AND STROUD, LIMITED, OF GLASGOW, SCOTLAND.

PERISCOPIC APPARATUS FOR RANGE FINDING, HEIGHT FINDING.

Application filed October 24. 1922, Serial No. 596,666, and in Great Britain November 1, 1921.

This invention relates to apparatus comprising two optical systems, one a first optical system of the range-finder class, the other a second optical system of the periscope class, the first system extending, say, horizontally, the second system extending, say, vertically and downwardly from the first system, and having the two systems associated so that rays from the first system may be directed into the second system.

The axes of the two optical systems remain perpendicular to one another, and in the following description it will be assumed that the axis of the first system is horizontal and that of the second system is vertical.

In apparatus to which this invention re lates the first system requires to be capable of angular adjustment about its horizontal axis, and the objectof this invention is to make provision whereby rays passing from the first system'at all angles to which it is adjustable about its horizontal axis may be automatically directed vertically into the second system and whereby the position of the focal plane of the image as seen in the second system may be maintained constant, and further to enable angular adjustment of the first system about its horizontal axis to be extensive.

The first system may be for rangefinding, heightfinding and the like, and will hereinafter he referred to as a rangefinder system and the second system as a periscope system.

The rangefinder system may be of the coincidence type associated with one periscope system or of the stereoscopic type in which case there may be two periscope systems or their equivalent, but the invention is not restricted to these particular types of range finders or periscope systems.

Some examples of construction according to this invention comprising a rangefinder system of the self contained base type and a single periscope system will now be described with reference to the accompanying drawings, in which Figure 1 is an elevation and Figure 2 is a side View illustrating one form of construction.

Figure 3 is a sectional elevation on a larger scale of a portion of Figure 1.

Figure 4 is an elevation illustrating a modification.

Figure 5 is a broken elevation partly in section and Figure 6 is a sectional plan, the

section taken being about the line XX of Figure 5, illustrating mechanism to be de scribed. i

In the construction illustrated at Figures 1, 2 and 3 a watertight upright casing A for the periscope system is provided having a watertight head casing A which extendslaterally from opposite sides of the upright casing A, within which a rangefinder B is so mounted as to be capable of angular adjustment about its longitudinal horizontal axis. For the admission of the rays of light to the apertures of the rangefinder, the head casing A is provided with watertight casing windows C of the requisite strength, the vertical lengths of which are such as to afford an unrestricted aperture for the beams of light within the required limits of the altitu-dinal rotation.

lVithin the head casing, see Figure 3, the rangefinder B may be supported upon roller, ball or other bearings which permit of its rotation about its longitudinal horizontal axis, for example, rollers 1 may be provided, and means may be provided for restricting the endwise movement of the rangefinder, for example, a roller 2 may be mounted upon the rangefinder B to engage with a groove formed in the interiorof the head casing, the groove being part of a circular groove cut concentric with the longitudinal horizontal axis of the rangefinder and in a plane normal to the axis.

Means of a kind described later are pro vided for the direction of the emergent rays of light from the angularly adjustable rangefinder into the optical system of the periscope.

For angular adjustments of the rangefinder about its longitudinal horizontal axis mechanism is provided which may be housed within the upright casing A and its head A For example, as illustrated, see Figures 1 and. 2, a shaft capable ofrotation and having a hand wheel D may be mounted to extend upwards through the upright casing A and be furnished at its head with a bevel pinion 3 in mesh with a bevel spur rack A fixed to the tubular casing of the rangefinder. In Figure 3 the pinion 3 and rackt are not shown.

In the construction illustrated at Figure 4 the periscopicupright casing A is provided with a covering head having tubular sleeves A which extend laterally from opposite sides. their outer ends for the reception of the rangetinder B the outer ends of which project beyond the outer ends of the sleeves, and in order to exclude water from the easing A watertight glands are provided between the sleeves A and the body of the r: ngefinder of a chaacter which permits the required angular adjustment of the rangelinder about its longitudinal horizontal axis. In this particular construction the portions of the rangetinder using which are located within and project beyond the glands are themselves watertight. and the rangelinder windows B are made sutliciently strong to withstand the water pressure when the rangetinder is sulinnerged. As in the construction Figures 1, 2 and 3. means are provided tor sup 'iorting the rangetinder B within the sleeves A for const aining it against: endwise movement. for angling the rangefinder ahout its longitudinal horizontal axis. and for directing the emergent b ams from the rangetindcr into the periscope system contained within the upright casing A.

It is desirable that. as the rangelinder B is rotated in altitude. the image of the target. should appear in the field of the periseope whenever the rangeliuder directed upon the target and that altitudinal movement of the rangetinder relative to the periscope should not attect the orientation ot the image ol' the field of view or to a serious extent the focus of the image.

An example of one. method in which these conditions may he satisfied is as tollowsz--- In front of the central prism system E. see Figure 5. of the rangetinder which comhines the heams of light from the two ends of the rangetinder there is mounted a reflector F, for examplera right -angled prism. which receives the rays of light proceeding. say, horizontally from the rangetinder and directs them downwards. say. vertically into the periscope system. The reflector l is carried upon the rangelinder. and moves with it, in altitude and therefore remains always in front ot the central prism system l l ot' the rangelinde' as the rangetinder is moved in altitude. It the retlector l were mounted rigidly in front of the central prism system, then. as the rangelinder was rotated in altitude. the emergent heam from the prism i would not follow a path parallel to a constant direction. namely the opti ral axis of the periscopc system. To ensure that the emergent heam will enter the periscorm in the required constant direction. unatlected hy the altitudinal movement of the rangetinder. the reflector l according to this method is mounted upon an axis pa 'allel or therehy to the longitudinal horizontal axis of the rangetinder and means are provided for rotating the reflector F through halt the angle traversed by the line of sight of the The sleeves A are open at rangetinder when moved in altitude. the direction ol motion of the reflector F heing such that the axis of the emergent beam re.- mains parallel to that ot' the periscope. The. rotation ot the reflector I may he etl'ected. say. through the intermediary of spur gearing having a ratio of 2: l. or. say. through the intermediary ol' levers whose arms are in the ratio of 2:1. or through a comltination of levers and gear wheels.

()ue arrangement which eomhines the use of levers and wheels will now he descrihed with reference to Figures 2- :3 and (5. In these views designates the longitudinal axis ol the rangctinder 1*). ti an axis parallel to .3. T a pivot carried hy and movin; with the rangetinder ll and R a pivot carried upon an arm 9 which rotates ahoutthe axis (5. The axes 5 and (3 are stationary relative to the periset'ipe. The pivots T and 8 move angularly in conformity with the rangetinder. 'lhe pivots T and t are connected hy a link It). The distance hetween the axes a and t is tixed and equal to the distance. lit-tween the axes ot the pivots T and 8. and sinc the radius J-J-T is equal to the radius (3 3. the tour form a parallelogram and, as the rangelinder l is moved in altitude, the radial directions 51-1" and (3-8 remain parallel. Similarly the connecting link I remains parallel to a line connecting I) and ti. As the line f (i is pa allel to the optical axis of the periseope A. the connecting link ltl also lies parallel to the axis whatever the. altitude movement of the rangetinder. From the upper end of the connecting link It! there projects at right angles an arm it which engages a pin 1:! ot a rocking arm 13 the spindle of which is provided with a pinion 14; in mesh with an internal spur rack 15 integral with a case It; which carries the ret'lector, a prism l Thus. the prism l is mounted to turn ahout the axis of the pivot T. The arm 11 remains always at right angles to the rod in. Thus, the angular movement of the rangelinder relative to the arm 10 is equal to the altitudinal rotation of the rangelinder I) relatively to the periscope. As the rangelinder is moved in altitude. the rocking arm l3 is acct'u'dingly moved angularly relatively to the rangetinder by an amount determined by the lengths o'l th" arms 11. and lit and the reflector F is rotated relatively to the rangefinder and therefore relatively to the cent :11 prism system E of the rangetinder by an amount determined hy the ratio of the arms 11 and 13 and of the gears 14 and '15. This combined ratio is made. such that the rotational movement. of the prism I is half that of the rangetinder.

In some cases. as for example in association with rangetinders ot the coincidence type. one reflector such as the prism F is employed. In other cases, as for example Inn Ill)

in association with stereoscopic rangefinders, two reflectors, which may be combined or mounted in the same case, may be employed. The reflectors may be of various forms according to the arrangement of the optical parts of the rangetinder and the periscope. In the arrangement described with reference to Figures 3, 5 and 6, the reflector F is a right angled prism of the roof type.

To maintain constant the position of the focal plane 01 the image in the field of view of the periscope as the rangefinder B is moved in altitude, one of the periscope lenses may be translated in the direction of the periscope axis by the requisite amount. For example, see Figure 5, the arm 9 is pivoted to rock about the axis 6, the rod 10 is pivoted to the arm 9 at the axis 8, and a holder 17 is also pivoted at the axis 8. The holder 17 carries an objective 18 of the periscope system whose focal plane is coincident with that of the rangefinder, the emergent rays from which are therefore parallel to one another. Upon the lower end of the connecting rod 10 there is a right-angled arm 19 which remains parallel to the arm 11. The outer end of the arm 19 engages with a pin 20 projecting from the holder 17. Thus, as the rangefinder is moved in altitude the objective 18 operates to preserve constant the focal plane of the image as seen in the periscope, the objective 18 being moved vertically by the rod 10 and maintained normal to the beam of light by reason of its support at the axis 8 and by the engagement of the pin 20 with the arm 19.

Associated with the altitudinal movement of the range-finder there is produced in this particular arrangement a small lateral displacement of the link 10 to or from the axis 5-6 and with it a lateral displacement of the objective 18, but, as the emergent rays are parallel to one another, such a displacement does not affect the position of the target image in the field of view of the periscope.

The various parts may be balanced by means of a weight G.

In the constructions illustrated H desighates the eyepieces of the periscopic system. Instruments according to this invention may also be provided with a trainers periscope system, for example, as indicated. in Figures 1, 2 and 4, comprising an eyepiece K, prisms 21. Q2 and window 23.

I claim 1. Apparatus comprising two optical systems one a range-finder system, the other a periscope system, the rangefinder system extending horizontally, the periscope system extending vertically and downwardly from the rangefinder system, the rangefinder system being movable for adjustment angularly about its longitudinal horizontal axis, first means movable for directing rays passing from the rangefinder system at all angles to which the rangefinder system is adjustable about its horizontal axis vertically into the periscope system, second means movable for maintainingconstant the position of the .i'ocal plane of the image as seen in the periscope, and means for moving the rangefinder and with it the first and second means all simultaneously for the purposes set forth.

2. Apparatus comprising two optical systems, one a rangefinder system, the other a periscope system, the rangefinder system having a tubular casing extending horizontally, the periscope system having a tubular casing extending vertically and downwardly from the rangefinder, the rangetinder extending laterally at opposite sides of the periscope system, and movable for adjustment angularly about its horizontal axis, first means for directing rays passing from the rangefinder system at all angles to which the rangefinder system is adjustable about its horizontal axis vertically into the second system, second means for maintaining constant the position 01 the focal plane'of the image as seen in the periscope, and means for moving the rangefinder and with it the first and second means all simultaneously for the purposes set forth.

3. Apparatus comprising two optical systems, one a rangefinder system the other a periscope system, the rangelinder system having a tubular casing, the periscope system having a vertical tubular casing and a covering head, the covering head having two tubular sleeves extending laterally from opposite sides of the periscope system said sleeves being open at their outer ends, the rangefinder being mounted in the covering head arranged with its longitudinal axis horizontally and movable for adjustment angularly about its longitudinal axis and having portions of the rangefinder projecting beyond the outer ends of said sleeves, first means for automatically directing the rays from the rangefinder axially into the periscopic support, second means for maintaining constant the position of the focal plane of the image as seen in the periscope, and means for moving the rangefinders and with it the first and second means all simultaneously for the purposes set forth.

1. Apparatus comprising two optical systems one a rangefinder system, the other a periscope system, the rangefinder system extending horizontally, the periscope system extending vertically and downwardly from the rangefinder system, the rangefinder system being movable for adjustment angularly about its longitudinal horizontal axis, a re fiector movable through half the angle of angular adjustment of the rangefinder and located in front of the central prism system of the rangefinder and at the top of the periscope system, an objective of the periabout its longitudinal horizontal axis. reflector means movable angnlarly for tlirecting rays passing from the rangelincler system at" all angles to which the rangeliniler system is adjustable about its horizontal axis into the periseope system, a lens of the periseope system movable by translation in the ilirection of the periscope axia. anti means for n'loving the r:in :etiniler anrl the reflector means angularly and the ions by translation all simultaneoufily. for the pnrposes set forth.

JAMES \YEIR FRENCH. 

